Since the founding of the American College of Nurse-Midwifery in 1955, nurse-midwifery experienced dramatic expansion in educational opportunities, numbers of graduate nurse-midwives, and numbers of practice sites. These developments were part of the two decades of social transformation ignited by demands for civil rights, women's liberation, and control over childbirth. Using the historical method this study will examine change and continuity over time; social structures; institutional forms of power; gender and class relations, and nurse-midwifery's transition toward autonomous practice within the context of mid twentieth century American ferment. Achievement of autonomy will be analyzed by examination of nurse-midwives ability to control entry into practice, regulation of practice, and the introduction of the birth center, an institution for nurse-midwifery practice, policy, and education. Methods include the study of primary archival documents, correspondence, organizational and practice records, original survey data, popular magazines of the period and oral interviews with nurse-midwives who practice during 1955-1980. Resulting knowledge will inform future developments in nurse-midwifery science, education, practice, and policy.